Cyprinid herpesvirus 3 (CyHV-3) is the causative agent of an extremely contagious and aggressive disease afflicting common corp Cyprinus carpio L. termed koi herpesvirus disease (KHVD). Since it was first reported in 1997, the virus has spread worldwide rapidly, leading to enormous financial losses in industries based on common carp and koi carp. This review summarizes recent advances in CyHV-3 research on the etiology, epidemiology, pathogenesis, diagnosis, prevention, and control of KHVD.